Laser alignment apparatus

Abstract

A building being erected is aligned with the vertical by projecting a main laser beam horizontally and splitting it into a vertically reflected test beam that is received on the building and used to ascertain proper alignment thereof with the vertical and a horizontally reflected adjustment beam that is received at a detector having an array of receptors around a central receptor. So long as the adjustment beam is received at the central receptor, the proper vertical positioning of the test beam is insured. If the adjustment beam moves off the center receptor, however, a positioning motor connected to the projector is actuated to reposition the main beam and the splitter to as to realign the adjustment beam with the central receptor and simultaneously realign the test beam with the vertical.

I claim: 
     
       1. An apparatus for aligning an object with the vertical, said apparatus comprising: a support adapted to be positioned adjacent the object to be aligned;   a housing limitedly tippable on said support;   means on said housing for projecting a main laser beam horizontally toward said object;   means on said housing including a mirror along and lying at an angle of 45° to the axis of said main beam and means for rotating said mirror about the main beam for splitting said main beam into a vertical and upwardly directed test beam orthogonal to said main beam and a horizontal adjustment beam orthogonal to said test beam;   means on said object remote from said housing for receiving said test beam for alignment of said object;   detecting means including at least one central receptor at a predetermined fixed location along said adjustement beam and offset from said test beam and a plurality of deviation receptors surrounding said central receptor for receiving said adjustment beam;   positioning means between said support and said housing for displacing said housing on said support and thereby moving said adjustment and test beams; and   control means connected between said detecting means and said positioning means for tipping said housing on said support when one of said deviation receptors receives said adjustment beam for realigning said adjustment beam with said central receptor.   
     
     
       2. The apparatus defined in claim 1, further comprising a second such detecting means facing the first-mentioned detecting means and offset horizontally by 180° therefrom relative to said main-beam axis.